When you're developing a service which has to communicate with a REST endpoint,
it is very likely that it will come in handy if you can convert some of your
objects to JSON (and back). Until recently, I always created a dictionary and
used json.dumps in that case. Also, when I wanted to log an object to
AWS Cloudwatch which has structured logs (json logs).
Instead of doing it completely manually, you should use a pattern described by jaraco (and fixed by me):
class MyCustom(object):
def __json__(self):
return {
"a": self.a,
"b": self.b,
"__python__": "mymodule.submodule:MyCustom.from_json",
}
for_json = __json__ # supported by simplejson
@classmethod
def from_json(cls, json):
obj = cls()
obj.a = json["a"]
obj.b = json["b"]
return obj
With that, the following workflow is possible:
import simplejson
obj = MyCustom()
obj.a = 3
obj.b = 4
json = simplejson.dumps(obj, for_json=True)
# Two-step loading
obj2_dict = simplejson.loads(json)
obj2 = MyCustom.from_json(obj2_dict)
# Make sure we have the correct thing
assert isinstance(obj2, MyCustom)
assert obj2.__dict__ == obj.__dict__
Note that we need two steps for loading. For now, the __python__ property
is not used.